Measurement of $D^0$ decays to $K^0_L \pi^0$ and $K^0_S \pi^0$ at Belle

TL;DR

This paper reports a preliminary measurement of the ratio of $D^0$ decay rates into $K^0_L o ext{hadronic}$ and $K^0_S o ext{pion}$ final states, aiding in understanding charm decay amplitudes and strong phase differences.

Contribution

It provides the first measurement of the $D^0 o K^0_L ext{pi}^0$ to $D^0 o K^0_S ext{pi}^0$ decay rate ratio using Belle data, improving constraints on charm decay parameters.

Findings

Measured decay rate ratio with statistical significance

Constrained the strong phase $\delta_{K extpi}$ between decay modes

Enhanced understanding of charm decay dynamics

Abstract

We present a preliminary measurement of the ratio of $D^0$ decay rates into $K^0_L \pi^0$ and $K^0_S \pi^0$ final states. This ratio can be used to disentangle the Cabibbo favored $D^0 \to \bar{K}^0\pi^0$ and doubly Cabibbo suppressed $D^0 \to K^0 \pi^0$ amplitudes, and contributes to the important goal of constraining the strong phase $\delta_{K \pi}$ between $D^0 \to K^- \pi^+$ and $D^0 \to K^+ \pi^-$. The measurement is based on a large data set accumulated by the Belle detector at the KEKB $e^+ e^-$ collider, with $K^0_L$ candidates reconstructed using hadronic clusters in the KLM ($K_L$ and $\mu$ identification system), together with a $D^0$ mass constraint and $D^{*+}$ tag.